Now click the 'MT4 - XL Series Installers' Tab tab as shown in the screenshot below
Open MetaTrader 4/5 and click 'File' and then select 'Open Data Folder' as shown in the screenshot below.
Right click in the data path field at the top of the windows explorer window and select 'Copy address as text' from the dropdown menu
IMPORTANT NOTE: The screenshot above shows the MQL4 folder selected but not opened... the MQL4 folder is a sub folder within the MT4 Data Folder. Do not mistakenly double click on the MQL4 folder and then click "copy address as text" ... in other words if you see 'MQL4' in your data folder path you're one folder too deep/ below the MT4 Data Folder. For MT5 installations you will see MQL5 rather than MQL4.
NOW CLOSE MetaTrader 4/5
The installer will now prompt you to enter the destination location for the product installation. Right click in the text field area and select 'Paste' from the dropdown menu as shown in the screenshot below
You will now see your MT4 / MT5 Data Folder location in the text field - Click the 'Next >' button to continue
If you see a pop up alert as shown below telling you the folder already exists - click the 'Yes' button
The installer is now ready to install - click the 'Install' button to complete the installation
VERY IMPORTANT: If you get Windows UAC prompts during the installation process make sure you ALLOW the installer to make changes on your computer.
If you get any error messages during the installation close MetaTrader and click the 'Retry' button
Click the 'Finish' button to complete the installation process
If you want to always allow DLL imports make a global change in the MT4 option menu. To do so - in MT4 / MT5 click 'Tools' / 'Options' and then select the 'Expert Advisors' tab. Now make sure 'Allow DLL imports' is ticked as shown below. This will always ensure "Allow DLL imports" is selected on product load.